Descending thin layer chromatography apparatus



N. PELICK June 10, 1969 DESCENDING THIN LAYER CHROMATOGRAPHY'APPARA'TUS Filed Feb. 10, 1966 VII/7717717 FIG.3

3 A v 4 3t 2 G F O 4 2 n v J A 6 I 2 nl "a l H] z 6 6 3 w m a w 4 Nicholas Pa'lick INVENTOR ATTORNEY United States Patent 3,449,083 DESCENDING THIN LAYER CHROMATOGRAPHY APPARATUS Nicholas Pelick, State College, Pa., assignor to Applied Science Laboratories, Inc., State College, Pa. Filed Feb. 10, 1966, Ser. No. 536,499 Int. Cl. G01n 31/08 US. Cl. 23-253 7 Claims ABSTRACT OF THE DISCLOSURE A cylindrical column mounted on a stage so as to be inclined close to the vertical position is divided into an upper solvent chamber, a development chamber positioned below the solvent chamber, and a valve between these two chambers to control the flow of solvent therethrough. The development chamber contains a chromatoplate having a groove therein in which are contained absorbent chemicals. The chromatoplate is positioned under the valve to allow the flow of solvent through the groove and to without the apparatus. A container is positioned under the groove to collect the flow of solvent therefrom. The sample components are eluted and collected into individual fractions which can be used for further analysis and/or quantitation of the component.

This invention relates to analytical apparatus and in particular to an apparatus designed so that samples to be analyzed can be separated by descending thin layer chromatography.

The science of thin layer chromatography, which has sprung into being in only recent years, has given impetus to the development of many specialized types of apparatus and techniques hitherto unknown in the analytical field. This apparatus is one of this type, primarily designed so that milligram samples which can be separated be descending thin layer chromatography, can be readily collected for subsequent uses. Such uses might be further identification of individual components by infrared, NMR, or other techniques. The apparatus consists of a developing chamber constructed of a heavy-walled glass cylinder mounted on a sturdy plastic stage with a solvent feeder located just above the chamber. A chromatoplate with a precision groove is mounted in the chamber after the sample is placed on the upper end of the groove, and the solvent is allowed to flow down from the feeder into the groove. The solvent and eluted components leave the end of the chromatoplate and drop into a vial placed through an opening located beneath the stage. The vials can be readily changed, thereby permitting a number of cuts to be taken.

It is an object of this invention therefore to provide a thin layer chromatography apparatus in which separation takes place in a controlled descending method.

It is another object of this invention to provide a thin layer chromatography separation apparatus operating by gravity feed by which the amount of solvent may be manually controlled.

It is yet another object of this invention to provide a thin layer chromatography separating apparatus by which samples may be easily and quickly collected.

It is yet another object of this invention to provide a separating apparatus having great sensivity.

It is still another object of this invention to provide a separating apparatus in which the solvent may be easily and accurately changed during operation.

It is another object of this invention to provide separating apparatus that can be quickly and easily disassembled and cleaned.

Other objects and a fuller understanding of this invention may be had by referring to the following description 3,449,083 Patented June 10, 1969 ice and claims, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 shows a plan view of an embodiment of this invention;

FIGURE 2 is a longitudinal view partially in section of the chromatoplate portion and its associated elements, shown in FIGURE 1;

FIGURE 3 is a cross-sectional view taken along the lines 33 of FIGURE 2;

FIGURE 4 is a plan view of the chromatoplate of FIG- URE 1 with a slurry absorbent applicator thereon.

Referring now to the drawings and in particular to FIGURES 1 and 2, 10 represents a cylinder, usually constructed of heavy-wall glass, mounted perpendicularly to and in the center of a square shaped stage 12. A cylindrical base 14 integrally attached to the top surface of stage 12 surrounds and supports the lower portion of cylinder 10 so that the cylinder 10 may be slideably inserted in base 14. Stage 12 is supported by two forward legs 16 extending downward from the front corner portions of stage 12, and two rearward legs 18 extending downward from the rear corner portions of stage 12.

Front legs 16 are longer than rear legs 18 so as to allow the stage 12 to be positioned about 15 from the horizontal.

The interior of cylinder 10 is divided into an upper solvent chamber 20 and a lower development chamber 22 by a cylindrical partitioning plug 24 inserted in the upper interior portion of cylinder 10; a disc-shape solvent cap 26 positioned on the top portion of cylinder 10 and a cylindrical shaped bottom plug 28 inserted in the bottom end portion of cylinder 10. An external O-ring 29 is positioned about the outer lateral surface of bottom plug 28 so as to bear against the internal surface of cylinder 10 thus retaining bottom plug 28 in position. Likewise two similiarly positioned O-rings 29 extend about the lateral surface of partitioning plug 24 so as to bear against the internal passage 38 surface of cylinder 10 and prevent solvent within the solvent chamber 20 from leaking past partitioning plug 24. A rectangular shaped chromatoplate 30 is supported between partitioning plug 24 and bottom plug 28 by means of upper and lower pins 32 extending from the top and bottom portions of chromatoplate 30 which are inserted in matching holes 34 in the interior surface of partitioning plug 24 and bottom plug 28.

The upper surface of the partitioning plug 24 has a hollow cylindrical valve body 36 perpendicularly mounted thereon with an internal passage 38 which extends through partitioning plug 24. A needle valve 40 is screwably positioned within the hollow valve body 36 and extends through the internal where it may be turned to adjustably control a fluid flow through the passage 38 into the developing chamber 22. When the needle valve 40 is positioned within internal passage 38, there is created an annular space between valve body 36 and needle valve 40. A horizontal solvent opening 42 extends laterally through valve body 36 to passage 38. As may be seen solvent which is contained within solvent chamber 20 may pass through opening 42 and controlled by needle valve 40 flow into developing chamber 22. A hollow cylindrical air tube 44 is perpendicularly positioned on the upper surface of partitioning plug 24 so as to rise above the level of the solvent in solvent chamber 20. A passage 45 through tube 44 into developing chamber 22 allows the air pressure to be equalized between the two chambers.

The component parts of this analytical apparatus are made of materials which are most inert and resistant to all chemicals which they may contact. For example, the square-shaped stage 12 is made of Plexiglas and has its top surface coated with a chemically resistant layer. A

Teflon, a tetrafluoroethylene resin layer, was found most satisfactory; although other resistant materials may likewise be used. Partitioning plug 24, bottom plug 28, valve body 36, and needle valve 40 are likewise made of Teflon, as is cap 26 and tube 44. It has been found that Teflon is particularly well suited for this purpose in that it is resistant to all solvents and easy to clean; although, of course, other chemically resistant material may be used. O-rings 29 are made of Viton, a fluoro elastomer resin, known for its resistance to fluids. The chromatoplate 30 is constructed of Delrin, an acetal resin also known for its chemical resistance and easy cleaning. Hence, it may be seen that the choice of materials make the analytical apparatus particularly chemical resistant and easy to clean and maintain.

Referring now to FIGURES 2 and 3, chromatoplate 30 has a longitudinally extending groove 46 positioned on the front surface thereof terminating on the upper portion at a passage 48 into which is inserted a perpendicular funnel 50 designed to direct the solvent flowing into the developing chamber 22, to the upper portion of groove 46. A V-shaped lower end 51 of the portion of groove 46 is V-shaped so as to direct solvent flowing downwardly through groove 46 to the tip of the V. Referring now to FIGURE 4, it may be seen that the cross sectional area of groove 46 is machined so as to flare outwardly, to contain a slurry of chemical later placed in the groove 46. A vial 62 is positioned in a cylindrical opening 53 in bottom plug 28 into the lower portion of developing chamber 22, directly below V-shaped lower end 51. Vial 52 is held within bottom plug 28 by a plastic O-ring 54 positioned within the interior of the opening 53 in bottom plug 28.

Referring now to FIGURE 4 there is seen a rectangular applicator 58 slideably positioned on the upper surface of chromatoplate 30 facing groove 46. Applicator 58 has a square opening 60 therethrough positioned directly above and extending to the groove 46. Lateral guides 62 of applicator 58 extend over the lateral edge of chromatoplate 30 so that applicator 58 may be drawn lengthwise over chromatoplate 30 guided by lateral guides 62.

In operation, the chromatoplate 30 is removed from cylinder and placed in a flat position with groove 46 facing upward. A rectangular applicator 58 with retangular hole 60 through is then placed upon the upper surface of chromatoplate 46 and a slurry of adsorbent chemicals, such as a silicagel, is poured into the upper opening of applicator 58 so that it flows into the groove 46. The applicator 58 is then drawn lengthwise down the groove 46 thus leaving groove 46 with a flat surface of silicagel therein which is then allowed to harden. A sample of the chemicals to be analysed is then placed on the upper portion of the hardened silicagel in the groove 46 and the chrmatoplate replaced in the developing chamber 20. The solvent chamber 20 is then filled with the appropriate solvent and needle valve adjusted so an appropriate amount of solvent will flow from the solvent chamber 20 through passage 42 and passage 38 into the funnel 50 and through passage 48 to the top of groove 46. Solvent will then flo wat a predetermined rate through groove 46 and the adsorbent material therein making the separation of the chemical to be analysed on the solvent. After the solvent has passed the length of groove 46, it collects at the tip of the lower V portion 51 thereof and drops into via 52. As may be seen the vial 52 may be removed during any portion of the separation and a new one replaced. Likewise the solvent within the solvent chamber 20 may be changed during any portion of the separation.

As may be seen the device described in a gravity feed type which finger tip control can be maintained over the solvent flow by means of the needle valve 40. A constant and continuous flow of the solvent may be thus maintained. Separation in this device take place as the de scending solvent flows through the adsorbent chemical within the groove 46.

Following use, the entire analytical apparatus may be quickly disassembled into its component parts and easily cleaned. This is done by removing cylindrical developing chamber 10 from base 14, removing the chromatoplate 30, partitioning plug 24, bottom plug 28, and their associated elements from the interior of the cylinder 10. All elements are then disassembled into their component parts, cleaned and reassembled ready for further use.

It is understood that the device described in the present disclosure is by way of example only and that numerous changes in details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

I claim:

1. An analytical apparatus for use in thin layer chromatography comprising in combination:

a solvent chamber, said solvent chamber designed to contain a chemical solvent;

a development chamber attached to said solvent chamber;

valve means in communication with said solvent chamber and said development chamber for controlling the flow of solvent from said solvent chamber to said development chamber;

a chromatoplate having a groove therein adapted to contain absorbent chemicals, said chromatoplate positioned in said development chamber with said groove in communication with said valve means to permit the flow of solvent from said valve means to said groove; and

a container positioned in communication with said groove;

whereby solvent passing through said groove will collect in said container.

2. The combination as claimed in claim 1 in which said groove has an outwardly flaring cross section to prevent absorbent chemicals contained therein from coming out.

3. The combination as claimed in claim 2 in which the end portion of said groove is V-shaped for directing solvent therethrough into said container.

4. The combination as claimed in claim 3 in which said valve means consists of a screw-type needle valve.

5. An analytical opparatus for use in thin layer chromatography comprising in combination:

a cylindrical container;

a partitioning plug positioned within said container to prevent the flow of fluid therethrough;

a needle valve positioned through said partitioning plug adapted to control the flow of fluid through said partitioning plug;

a funnel positioned in communication with said needle valve within said cylindrical container, and adapted to receive the solvent flowing through said needle valve;

a chromatoplate having a groove therein, adapted to contain absorbent chemicals, said groove positioned adjacent to and in communication with said funnel and adapted to receive solvent from said funnel;

a V-shaped section connected to the end portion of said groove;

a container positioned adjacent to said V-shaped section and adapted to collect the solvent from said V-shaped section;

a bottom plug positioned at the end portion of said cylindrical container; and

a vent tube extending through said partitioning plug within said cylindrical container to a height above the level of solvent contained above said partitioning plug.

6. The combination as claimed in claim 5 in which the cross section of said groove expands outwardly so as to readily contain absorbent chemicals positioned within said groove.

3,449,083 5 6 7. The combination as claimed in claim 6 having 9. 3,189,541 6/ 1965 Brenner et a1 23-230 XR stage upon which said cylinder is positioned, said stage 3,327,857 6/1967 Kopp. being inclined at an acute angle from the horizontal.

MORRIS O. WOLK, Primary Examiner.

References Cited 5 R. M. REESE, Assistant Examiner.

UNITED STATES PATENTS 2,487,574 11/1949 Meng. US. Cl. XR 3,146,163 8/1964 Brewer 23253 XR 23230; 73--61.1; 21031, 198 

